Electric meter



7 Sheets-Sheet 1.

(No Model.)

T. DUNCAN. ELECTRIC METER. No. 551,436. Patenized Deo. 17, 1895.

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T. DUNCAN. EEEGTEIG METEE..

Patented Dec. 17, 1895.

(No Model.)

EDUNGAN. ELECTRIC METER.

7. Sheets-Sheet 3.

Patented Dec. 1' 7, 1895.

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T. DUNCAN. ELBGTRIG METER,

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T. DUNCAN. BLBGTRIG METER.

No. 551,436. Patented Deo. l?, 1895.

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T. DUNCAN. ELEGTMG METER. No. 551,436. Patented Dec. 17, 3.895.

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UNITED STATES PATENT OFFICE.

THOMAS DUN CAN, OF FORT WAYNE, INDIANA.

ELECTRIC METER.

SPECIFICATION forming part ofLetters Patent No. 551,436, dated December'17, 1895.

Application filed July ll, 1895.

T all whom t may concern:

Be it known that I, THOMAS DUNCAN, a citizen of the United States,residing' at Fort W'ayne, in the county of Allen, in theSta-te ofIndiana, have invented certainl new and useful Improvements in ElectricMeters, of which the following is a specification.

Hy invention relates to that class of meters known as inductionmotor-meters, for measuring or integrating the number of couloinbsconsumed or used on alternating-current systems of distribution. Itsobject is to overcome a defect that is present in all meters known to meot this type at the present time. This defect is the dissipation of toomuch energy as C2 It loss in the series field-coils which usually carrythe current to be measured.

In my improvement I have shown a method of obtaining a torque fequal tothe best meter uponthe market of this induction type, and only use aboutone-half the length of wire and one-half the number of turns in theseries coils to accomplish it, thereby reducing1 the loss in the meterto the smallest possible amount.

My improvement also reduces the choke or impedance set up in the saidseries field-coils. The reduction of this impedance in said series coilswill prove valuable by its allowing the incandescence of the lamps toremain constant, and notdim them down as the meter is loaded, as is toooften the case with other meters. Since this impedancevaries directly asthe current and as the square of the number of turns in the seriescoils, it is at once evident that its influence as compared with othermeters is negligible when the number of turns have been reduced toone-half.

I also find that my improvement eliminates the humming noise sotroublesome with alternating-current meters, being a fault that hascaused central-station men to remove meters from private dwellings inmany cases. This reduction of noise is due to the density of field-fluxbeing only one-halt that of any other meter, or in other words, myimproved meter when upon full load has only the same density of flux asthe best induction-meter upon the market at one-half load.

Figures i to 40, inclusive, serve to show the manner in which I carryout my inven- Serial No. 555,638. (No model.)

tion, and in which similar characters refer to similar parts throughoutthe several sheets. Fig. l is a front elevation of my improved meter,whi le Fig. 2 shows the same in section, with another sectional planview shown in Fig. 3. Figs. 'i, 5, G, 7, S, 9, 10,11, 1213,14, l5, 1G,17, 18, 19, 20, and 2l illustrate some of the various methods ofconnecting and operating myimprovement. Figs. 22 and 23 show a diskemployed in lieu of a cylindrical armature. Fig. :25 shows a cylindricalarmature in the form of an inverted cup, with a sectional view of sameshown in Fig. 26. Figs. 27 and show another form ot cylinder which isprovided with a spider 59. Fig. 24 is a side elevation, and Fig. 28 aplan view, of the diverter. Figs. 2S), 30, 3l, and show various forms ofthe sheet-iron punchings which may be used in building up the core ofthe diverter 40. The recess upon the periphery of the hole at the centerand into which a pin fits is to prevent slipping of the diverter when inplace upon the upright tube which carries said pin and connects it withthe leverarm. Fig. 30 is a side view of the stamping shown in Fig. 29.Figs. 34 and 35 show the jewel post or stud upon which rests the spindieof the meter. Figs. 3G and 37 are views of the clamp used to hold theseries coils in position. Fig. 3S shows a form of armature whichconsists of a spiral of iron wire 44 placed upon the bent arms of aspider 43, while Fig. 39 shows rings of the same metal placed upon thespider orvertically-supporting arms of same. Fig. #l0 is a series coilin section showing the form of winding which I have 'ound to give thebest result.

The principal elements employed in the construction of my improved meterare a se ries coil or coils of insulated wire connected in the maincircuit and through which the main portion or all of the currentpassesfor the translating devices; a diverter which consists of one or morecoils of finer wire wound upon a laminated iron core and placed withinthe field of said series coil or coils, and having the terminals or endsof its coil connected in shunt to the terminals of the said series orthick-wire coils; a cylindrical armature mounted upon a suitable spindleand revoluble between the said series coils and diverter 5 IOO a wingedfan secured to the same spindle as the revoluble armature, and aregisteringu train for recording the number of revolutions made by thesaid armature.

In constructing my improved meter I employ a cast base 31, which isprovided with strengthening-ribs 2S and 29, a boss 20 for supporting thejewel-post 57, the lugs 56 and the back 9. Resting upon this base isalso a cast arch 5, which is secured upon bosses by the screws 52. Thisarch carries upon its two brackets 14 a cast part 11 for supporting theseries coils and diverter, a bearing at the top into which the upper endof the spindle enters, and the registering train or dial; The thick-wireor series coils are shown to be connected in multiple, Fig. 3, and theirterminals 7 and 24 secured to the binding-posts 37, which also comprisethe clampingplate 36 and the screws 34 for tightening saidcoil-ternii/nais between the parts 36 and 37. The connection s with thecircuit are made through the base of the meter and enter the hole 54 ofthe binding-post, in which the leads are secured by the screws 34. Thesebinding-posts are insulated from the back E) by the blocks of porcelainS, and are screwed thereto by the screws 3Q. The heads of these screwsare countersunk to prevent their touching the bach 9. The perce-lainblocks S are screwed to the back 9 with the screws 39, which must alsobe countcrsuuk or have a piece of mica cemented upon their heads toprevent their making contact with the binding-post 37. Underneath thesebinding-posts is placed a punched sheet of insulating material ,35, andhaving a hole through which the inleading wire from the circuit passes,which prevents it from coming in contact with the base. Thisinsulating-punching is screwed to the base with the screw 4G.

The series coils 4 are secured to the cast-- ing 11 by the punchedclamps 21, with their upright gripping extensions :26,which hold thecoils iirmlyin place. The slot 27 in this clamp allows the coils to beadjusted to the proper position when they are rigidly fastened to thebosses 23 lot" the casting 11 by the set-screws and washers 22.

The armature 6 which is located within the series coils 4 is mountedupon the spindle v3, said spindle resting` upon the jeweled bearing 58,which is at the top of the stud 57 and placed within the cap 17., whichprevents the entrance of dust, as well as serving to raise said spindleup outot' the said jewel when not in use. The four-winged fan 13 is ofthe ordinary construction with the exception of the beveled part 16which is forthe cap 17 to engage with for raising the spindle. Thespiral spring 1S is to keep the cap in any position in which it may beplaced upon the threaded part on top of the post 57 and upon which itturns.

The space 53 which is directly underneath the jewel-post 57 is forilling with wax or other suitable material to prevent customers fromtampering with said post. After adjusting the jewel-post it is tightenedin the boss 20 with the jam-nut 19.

The lugs 56 are provided with suitable holes 30 for securing the meterto its support when being installed.

For transmitting the revolutions of the spindle to the registering-train2 a worm 51 is used which meshes into the Worm-wheel 50. The jam-nut 49holds the upper bearing 4S in the cast arch 5.

The diverter 40 which is placed within the armature 6 is mounted upon atube 25 which is soldered to the lever-arm 10 and adjustable for varyingthe angle of the diverter. lVhen the proper angle has been obtained thisleverarm is screwed fast to the extension with the set-screw and washer12. In order that the diverter and its tube which connects it with thelever-arm for adjustment may be kept in a vertical position7 a secondtube 55 is used and which is soldered or otherwise suitably secured tothe cast plate or support 11. This tube extends upward into the divverter and makes an excellent bearing upon which to adjust it until therequisite speed or torque has been obtained by varying the angle of thelever-arm 10 which controls it.

The registering-train 2 may be made to read in either lamp-hours orampere-hours. Said train has two pins 1 which extend out from the taceof the vdial to about the saine distance as the hands or pointe-rs, toprevent the cover of the meter from striking and bending said pointers,which often results in their stopping the meter, this being a source ofconsiderable annoyance in handling a great many meters.

Fig. 6 shows the method of connecting the series coils 4 in the maincircuit a and l), the current being received from the transformer g andfeeding the lamps c. The diverter 40 in this figure is shown to be atabout an angle of thirty degrees, but gives the best results when saidangle is forty-five degrees. This diverter consists of two coils ofinsulated wire, one placed upon each end of the laminated iron core 40,and connected in series with each other, the remaining or outerterminals being connected in shunt or parallel to the series field orthick-wire coils 4. Vhen an impulse of current comes from thetransformer g, it is divided, the greater part flowing through theseries coils 4 and the remainder through the diverter-coils- Since thereis practically no impedance in the series coils 4, as hereinbeforementioned, the flow of current from -g will be instantaneous or in stepwith the electromotive force; but the current which traverses thediverter-coils will lag behind the current in the coils 4, therebyproducing a 'difference of phase between these two ii'elds which causesthe aluminum cylinder or closed secondary G to revolve in a directionwhich is counter-clockwise, due to the well-known shifting-held effect.This would also be true if the iron core was removed IOO IIO

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from these divertercoils and placed in a separate coil in series withthem, so as to give this diverter-circuit the necessary lag orimpedance; but by so doing the speed would be very perceptibly reduced;but by using the iron core it develops another torce which is added tothat produced by the aforementioned shifting-field effect-viz., arepulsive force set up between the series coils 4C and the aluminum drum6 which drives or repels said drum around in the same direction as thatin which the shifting-field drives it, thereby increasing the efficiencyto a very perceptible degree. This repelling force is established by theflux from the coils 4 cutting obliquely through the aluminum drum 6 inits path through said iron core of the diverter, causing it to revolvein the -1nanner stated. Then the flux of the series or thickwire tieldpasses through the coils of the diverter, it also develops a secondarycurrent in these coils, which will be in step with and have the samedirection of flow as the current shunted from the terminals of the coilset on the side of the circuit a. The torque is zero when the diverter isin the same axial plane as the series coils and at a maximum when at anangle of forty-rive degrees. If moved around to ninety degrees, it stillrotates, but with diminished speed, due to the repulsive force betweenthe series coils @L and the closed secondary Ghaving disappeared. Forthis reason it gives the best results when the diverter is at the angleof forty-iive degrees, since the repelling force moves toward the axisof rotation when the angle is varied on either side of forty-fivedegrees, being exactly through the center when at zero and ninetydegrees. Another reason why the torque is reduced when the diverterstands at right angles is that the diverter-coils are not cut by theseries field-flux, therefore do not have the secondary current inducedin them which works in conjunction with the current derived from theterminals of the series coils 4f.

Fig. 7 shows the same arrangement of the coils 4, the diverter-terminalsbeing connected or shunted around only one of the series coils.

Fig. 8 is similar to Fig. 6 in that its diverterterminals are connectedto thev terminals of the coils l, but has also another wire connectingthe center of said diverter-coils with the center of the series coils inthe manner shown. This arrangement is for balancing the forces actingupon the drum G, in case that either the two coils 4 or thediverter-coils respectively should happen to have or acquire a differentimpeditive value from each other, which would produce resulting complexshifting elds that might interfere with the regulat-ion and accuracy ofthe device as a meastiring-instrument.

In Fig. the series coils et are connected in multiple to each other, asare also the terminals of the diverter-coils.

Fig. 10 has an impedance-coil connected in series with thediverter-coils for varying the speed of the armature by the adjustmentof the iron core contained and shown within the coil or windingsurrounding it. I have also made use of this arrangement in measuringthe watts consumed by connecting one of the terminals of thisdiverter-circuit to the other or h side of the mains. Finding that thebest results are obtained when the resistance of these diverter-coilsand their impedance bear a certain relation to each other I use anadjustable resistance d in series with them, as shown in Fig. 1l, also acombination of both the said resistance d and the impedance-coil c ofFig. 10.

In Fig. 12 is shown one of the divertercoils connected in series with avariable resistance d, while the other is connected or shunted aroundonly one of the coils 4.

Fig. 13 is similar to Fig. 7 with the exception of showing the seriescoils in multiple to each other.

For the purpose of overcoming the friction of the moving parts of themeter I have used the method shown in Fig. 14, in whicha supplementalcoil 4A is used to produce an initial iield or torque. This coil orsupplemental exciting-held is connected in series with a non-inductiveresistance d and the remaining terminals connected to the mains a and bin multiple, as shown. It is necessary for the successful operation ofthe meter that there be littleor no self-induction in this supplementalcoil 4^.

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Fig. 15 shows another method of connecting the diverter 40 by shuntingthe terminals of one of the coils around the series field-coils, whilethe remaining coil is placed in series with a variable reactive coil c,the ends being connected across the mains a and b. By varying the amountof impedance in the coil c the speed of the cylinder 6 is adjusted untilit is correct, thereby making this IIO arrangement very simple andeffective in calibrating the meter.

Fig. 16 is much similar to Fig. 15, but has added the supplementaryexciting-coil A of Fig. 14. The adjusting of c may be accomplished byeither moving the core in or out.

For measuring the output of central stations the series coils maybeconnected in the.

main line, as shown in Fig. 17, between the dynamo g and thetransformers or other translating devices e.

Fig. 18 shows the diverter-coils at right angles and where only theshifting eld aforementioned causes the aluminum drum or cylindricalsecondary 6 to rotate. However, if I employ an iron cylinder with theseries coils and diverter, as shown, I obtain the best torque with thismagnetic metal at this angle. Another distinction between the twoarmatures is' that they will revolve in opposite directions. This isdueto the poles of the two armatures diiering in the following manner: Whenan iron armature or cylinder is used, its induced magnetic poles will beopposite f netic metal--such as copper, aluminum, or

silverbe used the induced poles which re-V suit from the iiow ofsecondarycurrents developed in the cylinder will have signs similar tothose of the magnetic poles which developed these secondary currents andof which they 'are the result, thereby setting up al repulsiveforce'between the induced currentn poles and their inducing-poles, incontradis'- tinction from the attract-ive force displayed between thedirect-induced magnetic poles in the iron cylinder and said inducing-poles, they being opposite in sign. Therefore, it is veryevi-dent that ifk rotation is produced inone direction with an aluminumarmature it will be reversed if an iron one is substituted.Notwithstanding the foregoing, the iron cylinder cany be made to revolvein the same direction as the aluminum one by'reversing the terminalconnections of kthe diverter-coils, thus changing the direc-Y tion ofthe current through them from the line c at the terminals of the coils4. I have also used this form for measuring the watts expended in singie-phase alternating-current work by placing the terminals of thediverter 40 across the mains a and band subjecting them to the drop ofsame, thereby representing the eleetromotive force by the fieldproduced. Y In its application to this use I employ a reactive coil c ofany suitable form to Y obtain the proper phase 'and speed. In two `phasework I have also used this form'by passing the currents iiowing in thecommon return through the coils i and joining the terminals of thediverter-coils to the outer leads of the system, with a variableresistance in series therewith to determine the speed. It is notnecessary that the iron core be used in two-phase work, since the angleof lag` between this diverter and the series coils is established andmaintained at ninety degrees by the generator.

Fig. 19 has one of the diverter-coils closed upon itself, the otherbeing connected in the usual manner.

Fig. 2O shows a condenser f and impedancecoil c in series with the coilsupon the diverter i0, while in Fig. 21 a variable resistance d is usedin combination with the condenser f instead of a reactive coil c, as inFig. 20.

I do not wish to be understood as limiting myself tothe methods ofapplying eondensers and impedance-coils as herein shown or described, asother methods are well known to those versed in the art.

Fig. 22 shows an aluminum disk 6A mounted so as to rotate between theseries coils 4, the upper of which has a laminated iron core placedwithin it.

In Fig. 23 the lower coil is in series with the main feeder, the upperone being closed upon itself.

Another method of obtaining rotation of the drum G is shown in Fig. 5.In this combination noV metallic connections with .the coils 4 or linesCL and l) are used. The coils of the diverter e0 are connected in serieswith .the coils 4A, all three of which act as a single closed secondarycircuit through the adjustable resist-ance d. In Fig. e these coils i*and ythose .of the diverter'i() have their terminalsk shunted around thecoils i, and may be connected in series with the impedance C ifnecessary, as shown by the dotted lines.

The arrangement of coils shown in Fig. i8 I iind to work well with thearmatures shown in Figs. 3S and 39.

One of the improved mechanical features of myy invention is intheconstruction of the jewel-post, Fig. 35, which consists in having aseparable part 58 in which is set the jewel,

very easily. users of electric meters who have to change damaged jewelsvery ofteineither on account of ktheir wearing out or cracking inhandling. f If a new jewel is to be inserted in a meter, all that isnecessary is to loosen the jam-nut 19, (see Fig. 2,) holding it with thespring i8 and cap 17 between the fingers and thumb, when the postV 57may be easily removed with a screwdriver from thebottom at the recess53. After removal, the settingS can be ex; changed for a new one andreturned in a few moments.

Fig. Li0 represents in section the form of coil with which I am enabledtofobtainY the best results. Itis wound so that the nuni ber of turnsper layeris equal to the number of layers, thereby giving a squaresection or that of a rectangle with all its sides equal, as shown. Itwill be noted that in Figs. l, 2, and 3 the eld-coils 4 have onlysixteen turns, this being a much lower number than that used by anyother meter of equal capacity new known to me at the present time. Thecover which fits upon the meter fits tightly around the outside of therib 29A and is fastened upon the lower side of the base 3l by a suitablenut which is screwed to the extension of the cover that passes throughthe hole -iLl in the front part of the meter-base.

My improvement also includes the manner of proportioning the axiallength of the series coils 4, which consists of making or adjusting themso that their greatest axial length will be equal to the outsidediameter of the cylinder, when the records of the meter follow anabsolutely-straight line law. This fact, to my knowledge, has neverbefore been made known or applied in practice, and is one of mostimportance in the construction of electric meters, since it has beenimpossible to produce them so that their rate of rotation would vary inabsolutely the same ratio as the current passing through them, but wouldvary say two per cent. fast on one load, three per cent. slow on someother load and possibly four per cent. fast again on another.

lVhat I claim is-A A l. The combination with an electric meter IOO IIO

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of a vertical spindle carrying an armature and retarding fans, avertical post adjustable in its bearing and having a jewel setting in aremovable or separable part at its upper end upon which the said spindlerotates, and a cup shaped. nut surmounting or covering said jewel andadjustable upon the said vertical post for the purpose set forth.

2. The combination with an electric meter, of a separable jewel setting58, a jewel post or studprovided at its upper end with an adj ustableinverted cup shaped nut 17, having a hole on top through which thespindle passes, and mounted upon a suitable threaded portion of saidstud, so that by raising it, it engages with the lower end of thespindle, thereby lifting it up out ofthe jewel in the said separablepart 5S for the purpose set forth.

The combination with an electric meter, of a jewel post or stud 57,having a spiral spring 18 which presses against the cup nut 17 on top,and preventing it from moving when subjected to any vibration afterbeing set or adjusted as herein set forth.

i, The combination with the iield coils of an electric meter, of thepunching, which consists of the extension fingers 26 for gripping saidcoils, and the slot 27 for adjusting said coils as herein set forth.

5. The combination with the motive part of an electric meter, foralternating currents, of

a diverter consisting' of a core of laminated' sheet iron or steel,having at its center a hole through which passes the spindle, andprovided with a coil of insulated wire at each end or pole as hereinshown and for the purpose set forth.

6. The combination with an elect-ric meter, of a diverter core built upfrom thin sheet iron punchings, and having a recess upon the peripheryof the hole at its center into which iits a suitable pin or rod toprevent the diverter from turning as herein set forth.

7. In an electric meter the combination of the diverter coils 4:0, theenergizing coils 1, the

.section of whose winding is that of a square or rectangle having allfour sides of equal length and a vertical shaft passing between saidcoils which carries a closed revoluble cylindrical secondary armature ofaluminum which is acted upon by the magnetism of said coils, and aretarding device for opposing the motion produced by said cylinder asand for the purpose set forth.

S. The combination in an electric meter of the series energizing coils4, the section of whose Winding is square or that of a rectangle havingall four sides equal in length, the diverter coils, an armature mountedupon a vert-ical spindle and revoluble therewith and having a diameterequal in length to that of the axis of said energizing coils for thepurpose set forth: a winged fan of aluminum mounted upon the samespindle as the said armature, and a registering train for indicating theamount of current or energy used.

9. In an electric meter for alternate currents, the combination with themotive part,

of the series or energizing coils 4, approaching from opposite sides thecylindrical armature G within which is a diverter 40 and adjustableconcentrically therewith, and an energizing circuit d l) as herein shownand for the purpose set forth.

10. The combination in an electric meter for alternating currents of theinducing coils 4C, the armature G revoluble between said coils 4, thediverter coils 40, and an impedance coil, which is connected in serieswith said diverter coils, the remaining terminals being shunted aroundthe coils 4 as set forth.A

11. In an electric meter for alternating currents, the combination withthe vertical spindle, of an aluminum drum or cylinder, and two sets ofmagnetizing coils; said cylinder being revoluble between said coils andclosely embraced by same, so that all the flux generated by these twocoils, 4C and 40 will eniciently cut said drum for the purpose setforth.

Signed byme, at Fort TNayne,Allen county, State of Indiana, this 6th dayof July, A. D. 1895.

THOMAS DUNCAN.

lVitnesses ELTON J. KING, BURLEIGH CURRIER.

